EP 0200022 A2 19861105 - Holographic optical display system with optimum brigtness uniformity.
Title (en)
Holographic optical display system with optimum brigtness uniformity.
Title (de)
Holographische Anzeigevorrichtung mit optimaler Bildhelligkeitsgleichheit.
Title (fr)
Dispositif d'affichage holographique procurant une luminosité d'image uniforme.
Publication
Application
Priority
US 72612585 A 19850423
Abstract (en)
[origin: US4655540A] An optical display system employs a holographic optical element that has a holographic fringe pattern which is coordinated with the phosphor emission peak of a cathode ray tube to eliminate perceptible variations in image brightness. The holographic optical element has a reflection characteristic that defines two diffraction efficiency peaks which are resolved by a low diffraction efficiency dip that is interposed between them. The optimum wavelength spacing between the two diffraction efficiency peaks for a given wavelength spacing is determined by computing for all observer head positions and look angles of concern the differences among the areas under the integrated efficiency characteristics for the reflection characteristic of the holographic optical element and the phosphor emission characteristic of the image-producing cathode ray tube. The optimum wavelength spacing is that which provides the desired variation among the computed difference values, which respresent the display brightness uniformity. The center dip reflection characteristic increases the spectral bandwidth of the holographic optical element and thereby increases its reflectivity to promote good contrast with the use of a cathode ray tube operating at reduced beam current levels. When installed as a combiner in a head-up display sytem for aircraft, the holographic optical element superimposes the image on an outside scene without introducing significant discoloration of the scene.
IPC 1-7
IPC 8 full level
G02B 27/01 (2006.01); G02B 27/00 (2006.01)
CPC (source: EP US)
G02B 27/0103 (2013.01 - EP US); G02B 2027/0109 (2013.01 - EP US); G02B 2027/0118 (2013.01 - EP US)
Designated contracting state (EPC)
CH DE FR GB IT LI NL SE
DOCDB simple family (publication)
EP 0200022 A2 19861105; EP 0200022 A3 19880413; JP S61289320 A 19861219; US 4655540 A 19870407
DOCDB simple family (application)
EP 86104568 A 19860403; JP 9316586 A 19860422; US 72612585 A 19850423